Starter systems for internal combustion engines are known from German Patent No. 197 09 298. The starter systems have a DC link inverter. This includes a DC-AC converter, a short-term energy accumulator, as well as a vehicle electrical system DC voltage converter. The components mentioned are controlled via a control device. The control device tells the converter the amplitude, phase, and frequency of the three-phase current to be supplied to the starter of a vehicle. Using the control device, the amount of current, the current direction, and the amount of the current increase or decrease is specified to the DC voltage converter. Furthermore, the control device tells a consumer control device the amount of current that may be removed from a short-term energy accumulator and the voltage difference to be overcome in the removal, if necessary. The starter motor requires additional energy from the short-term energy accumulator during the start phase.
After the start, the starter motor works as a generator and provides the intermediate circuit with energy via the converter. The design of the vehicle electrical system DC voltage converter as a bi-directional converter makes it possible to bring electrical power from the vehicle battery into the intermediate circuit and to transfer power from the intermediate circuit to the low-voltage side when the starter motor is generator-operated after start. The vehicle electrical system's consumers may be supplied and the vehicle battery may be charged again during this process.
The subject matter of German Published Patent Application No. 100 62 075 A is a converter with integrated intermediate circuit capacitors. The converter is connected to a voltage intermediate circuit exhibiting a charge accumulator. The converter according to this approach may contain either a half-bridge circuit or a bridge circuit. This circuit forms a module situated in a housing. The charge accumulator is divided into several intermediate circuit capacitors, of which one, several, or all form an integrated component or components of the module.
In three-phase generators currently used in vehicles, their rectifiers are often made of passive components. High-blocking capability diodes or Zener-diodes may be used for this. High-blocking capability diodes work like a flow control valve and are therefore suitable semiconductor components for rectifying alternating currents. The current in blocking direction may be up to 107 smaller in comparison with the forward current. The latter rises sharply with increasing temperature. In Zener-diodes (Z-diodes), when the voltage increases in reverse direction starting from the time a certain voltage is reached, there is a steep rise in the current as a result of the Zener and/or avalanche breakdown. Z-diodes are designed for continuous operation within the breakdown region. The most common type of assembly of the mentioned semiconductor components is pressing in the diodes into a heat sink or into a cooling plate. In addition, these diodes may also be pressed directly into the end shield of a three-phase generator. Aside from the semiconductor components, the electronics of the three-phase generator includes a controller with which the excitation current as well as the freewheel are controlled.